Self-adjusting pusher rod



1934- o. F. FREDRICKSON 1,933,127

SELF ADJUSTING PUSHER ROD Filed May 27, 1955 I Invenior Oscar I? Fredr'on BY Att Zne y 25;: of engine valve pusher rods.

adjustable to compensate for wear in variations Patented Dec. 4, 1934 UNITED STATES PATENTOFFICE.

Application Mayzv, i933, Serial No. 673,151

11 Claims. (o1. 123-90) This invention relates to pusher rods and more particularly to self-adjusting pusher rods, al-

though certain features thereof may be employed with equal advantage for other purposes.

I It contemplates more especially the provision of novel self-adjusting pusher rods for internal combustion engines so as to compensate for wear and avoid clearance without requiring any man ual adjustment or replacement.

Pusher rods of numerous types have heretofore been employed and are required as the operating medium between engine valves and the actuator constituting, in most instances, a cam mounted upon crank responsive shafts. 1 Variations in temperature and the repeated operation of valves at very high speeds, clearances present themselves between the valve stem, pusher rod and actuator to the end of producing noises, improper valve operation and undue wear. :1 These are not conducive to efficient engine operation and substantially increase the cost of maintenance.

One object of the present invention is to simplify theconstruction and improve the operation Another object is to provide novel means for rendering the pusher rod self-adjustable to variations in clearances to afford the smooth operation and properly timed valve actuation.

Still another object is to provide novel and simple means for rendering pusherrods selfresponsive to temperature influences. I r A further object is to provide a novel expef1 client to compensate for all pusher rod clearances which develop in consequence of engine opera-f tion. thereby avoiding improper valve operation and eliminatingthe afiects of wear.

Still a further object is to provide means in conjunction with pusher rods to render such selfadjustable to variations between the valveand its actuator. j

A still further object is to provide a pusher rod havingrelatively movable parts which are capable of self-adjustment responsive to the degree of frictional. reaction influenced by the available clearance in conjunction with a valve and its actuator.

Other objects and advantages will appear from the following description of an illustrative embodiment of the present invention.

In the drawing:

Figure 1 is a fragmentary sectional view in elevation of an engine block showing its valve,

In view of the actuator, and pusher rod mechanism embodying features of the present invention.

Figure 2 is an enlarged fragmentary sectional View of the self-adjusting pusher rod embodying features of the presentinvention.

Figure 3 is a perspective view of the pusher rod shown in Figures 1 and 2, parts thereof being broken away to clarify the showing. 1

Figure 4 is a sectional view taken substantially along line IV-IV of Figure 2.

Figure 5 is a sectional view taken substantially along line V-V of Figure 2.

The structure selected for illustration is shown in association with an engine block having the usual valve 11 cooperating with a valve seat 12 for controlling the intake and exhaust to the cylinder in communication therewith. The valve 11 has an elongated stem 13 which is reciprocally mounted in a guide 14 depending from the cylinder head 14 of the engine block 10. The valve guide 14 is provided with the usual exteriorly threaded shank 15 which receives a spring adjusting nut 16 and its cooperating lock nut 17. The spring adjusting nut 16 has a depending collar 18 for the reception of the valve spring 19 thereover.

A disc shaped washer 20 is carried by the valve stem extremity 21 which has a pin 22 extending diametrically therethrough so as to limit the movement of the spring washer 20 to sustain the spring 19 against the adjusting nut 16, thereby normally maintaining the valve 11 in contact with' its seat 12 to preclude the passage of the fuel charge to the engine cylinder in the event the valve 11 serves as an intake control or to preclude the discharge of the gases from the cylinder to the exhaust in the event such serves as an exhaust valve. l

The opening and closing of the valve 11 is usually controlled by a cam 23 which is mounted on shafts 24 responsive to and operatively connected with the crank shaftof an internal combustion engine. In order to enable the cam 23 to actuate the valve 11 responsive to the rotation thereof, a pusher rod 25 is reciprocally mounted in a guide 26 sustained in a flange 27 preferably though'not essentially constituting a part of the engine block 10. As shown, the pusher rod 25 is preferably of cylindrical configuration and terminates in an enlarged circular head 28 for normally contacting the cam 23 throughout the surface extent thereof responsive to the influence of the valve stem 21 which is normally urged thereagainst responsive to the valve spring 19. It is necessary or at least highly desirable that the pusher rod 25 serve as a connecting medium between the valve stem extremity 21 and the operating cam 23 to convert the rotary movement of the latter to reciprocal movement of the former, and this is best accornplished by avoiding any undue clearances between the actuator 23 and the actuating valve 11. This is best accomplished by providing a self-adjusting expedient in connection with the pusher rod 25 so that its longitudinal extent may be automatically increased or decreased depending upon the requirements and the relative variations between the irregular surface of the cam 23 and the valve stem extremity 21.

To this end, the pusher rod 25 is provided with a cylindrical cavity 29 extending from the free end thereof to receive instrumentalities which will be described more particularly hereinafter. The pusher rod cavity or bore 29 terminates in an enlarged portion 30 for communication with the open end of the pusher rod 25 so as to present a peripheral shoulder 31. As shown, the pusher rod bore 29 with its enlarged portion 30 receives a correspondingly shaped sleeve 32 having a cylindrical body 33 and an enlarged peripheral shoulder 34 for detachable reception within the bore 29 to rest against the peripheral shoulder 31 thereof. The enlarged cylinder 34 of the sleeve 32 presents a flat surface 35 substantially in alignment with the top peripheral edge 36 of the pusher rod guide 26 which has diametrically opposite upstanding extensions 37, in this instance two, for registry with a disc 38 having correspondingly shaped slots 39 for that purpose.

The disc 38 corresponds in circular dimensions with the top portion of the guide 26 and rests thereon so that the flat surface 40 thereof will contact and frictionally react with the flat surface 35 of the sleeve 32 for reasons which will appear more fully hereinafter. As shown, the disc 38 terminates in a series of upstanding concentrically arranged shoulders 41 and 42 which diminish in diameter to present an annular shoulder 43 so that a spiral spring 44 may be engaged therewith. The spiral spring 44 'envelops the shoulder 42 and its enlarged concentric shoulder 41 is of a diameter corresponding with the enlarged shoulder 34 of the sleeve 32 so as to be received within the enlarged portion 30 of the pusher rod bore 29. In order to enable the pusher rod 25 to be increased or decreased in longitudinal extent, an elongated stud 45 is operatively connected with the frictional member or disc 38. To this end, the exterior of the stud 45 is provided with a comparatively high pitch thread 46 to mesh and engage with the correspondingly .threaded axial bore 4'7 provided through the frictional disc member 38 with its concentric shoulders 41 and 42. The exteriorly threaded stud 45 is provided with an enlarged circular head 48 which is adapted to contact the valve stem extremity 21. A tubular sleeve 49 of cup-shaped configuration is provided with an axial aperture 50 to receive the stud 45 therethrough and to telescopically engage the shoulder 41 of the frictional member 38. In consequence thereof, the tubuj lar sleeve 49 is disposed below the head 48 of the stud 45 and confines the spiral spring 43 in enveloping relation with the shoulder 42 integrally or otherwise formed in conjunction with the shoulder 41 and the friction disc member 33.

. It is to be noted that the exteriorly threaded stud 45 is milled diametrically therethrough to provide a slot 51 extending for a substantial portion thereof from the bottom extremity 52 thereof. The sleeve 33 is correspondingly slotted as at 53, and a fiat key or plate member 54 extends through the slots 51 and 53 for confinement with the pusher rod bore 29 to maintain the threaded stud 45 and sleeve 32 against relative rotation. In consequence thereof, the threaded stud 45 and its sleeve 32 will rotate relative to the frictional disc member 38 which has its flat surface 40 in frictional contact with the fiat sleeve surface 35 responsive to the urge of the spring 44 and the valve spring 19.

The pitch of the thread 45 is such as to present minimum friction relative to the correspondingly threaded bore 4'7 of the frictional member 38 so that the spring 44 will be capable of urging the stud extremity 48 in contact with the valve stem extremity 21 when the frictional reaction between the surface 35 and 40 is released in consequence .of the lacking urge normally imparted by the valve spring member 19. As a result the stud 45 of the pusher rod 25 will be extended to its maximum degree necessary to preclude any clearance between the pusher rod 25 and its actuator 23 on one end and the valve stem extremity 21 on the other end. When any clearance presents itself between the actuator 23 and the valve stem extremity 21 in consequence of wear and temperature variations, then the valve spring 19 will cease to exert any influence on the pusher rod stud 45 and as a result the cooperating frictional surface 35 and 40 will be separated to enable the spring 44 to urge the stud 45 outwardly until frictional member 38 engages the surface 35 of the enlarged surface 34 constituting a part of the sleeve 32.

The newly created frictional reaction between the surfaces 35 and 40 will establish a rigid relation between the stud 45 and its supporting pusher rod-25, thereby transferring the impulses from the cam 23 to the valve stem 13 without any clearance therebetween. As soon as any clearances are again existent or present for any cause whatsoever, the surfaces 35 and 40 will once more separate or the frictional reaction reduced to such an extent as to enable the spring 44 to automatically readjust the position of the stud 45 relative to its supporting member 38 to eliminate any clearance. Should the valve stem 13 or any of the other parts expand in consequence of temperature variation or for other reasons, and an undue stress would ordinarily be imparted to the pusher rod 25, then the urge of the valve spring member 19 will be sufficient to overcome the frictional reaction between surfaces 35 and 40 to enable the threaded stud 45 to rotate within its supporting member 38 so as to reduce the degree of extension therefrom and relieve the undue stress occasioned by the expansion of any of the parts.

It will be apparent, therefore, that the pusher rod 25 and its auxiliary instrumentalities including the externally threaded member 35 will be self-adjusting to afford the proper operation of the valve 11 responsive to its actuator 23. During normal operation and when the clearances are not excessive or existent, the pusher rod 25 presents a solid connecting-medium between the valve stem extremity 21 and actuator 23 by virtue of the fact that the frictional reaction between surfaces 35 and 40 of the cooperating members 34 and 38, respectively, preclude any relative rotation between the stud 45 and its supporting member 38 and the spring members 19 and 44 do not directly sustain the instrumental ities in connection with the pusher rod 25.

Various changes may be made in the embodiment of the invention herein specifically describedfwithout ilepartingfrom or sacrificing any of the advantages of the in vention as" defined in 1 sleeve movably' associated with said pusher rod, a*

l valve st'em en'gaging member associated with said sleeve for rotation therewith, a member l in threaded engagement" with said valve stemenan gmemp r ffor fr'ictional contact with said sleeve and pusherrod,;and aspring for normally urging saidlastnamed 'mernber infrictionalcontactwithsaid sleeve andpusher-rod to preclude relative axial displacement betweem said inter-- threaded valve stem engaging and friction mem- L bers. I v m 2.,Ina device of thepharacter described, the combinationwith' a pusher rod adapted for reciprocation in alignment with an engine valve, of a sleeve movably associated with said pusher rod, a valve stem engaging member associated with said W sleeve for rotation therewith, a cylindrical collar 2 member in threaded engagement with said valve stem engaging member and splined to said pusher rod for frictional contact between said sleeve and pusher rod, and a spring for normally urging said last named member in frictional contact with said sleeve to preclude relative axial displacement between said inter-threaded valve stem engaging and friction members.

3. In a device of the character described, the combination with a pusher rod adapted for reciprocation in alignment with an engine valve, of a sleeve movably associated with said pusher rod, a valve stem engaging member in splined association with said sleeve for rotation therewith, a member in threaded engagement with said valve stem engaging member and splined to said pusher rod for frictional contact with said sleeve, and a spring for normally urging said last named member in frictional contact with said sleeve to preclude relative axial displacement between said ifi inter-threaded valve stem engaging and friction members.

4. In a device of the character described, the combination with a pusher rod adapted for reciprocation in alignment with an engine valve, of a i sleeve movably associated with said pusher rod, a valve stem engaging member in splined association with said sleeve for rotation therewith, a member in threaded engagement with said valve stem engaging member and splined to said pusher rod for frictional contact with said sleeve, a spring for normally urging said last named member in frictional contact with said sleeve to preclude relative axial displacement between said interthreaded valve stem engaging and friction memfbers, and an axially apertured cap mounted on said valve stem engaging member for cooperation with said friction member to confine said spring therebetween.

5. In a device of the character described, the combination with a pusher rod adapted for reciprocation in alignment with an engine valve, there being an elongated bore in said pusher rod, a tubular collar rotatively mounted in said pusher rod bore, a disc-shaped member adapted for sur- -face contact with said collar, inter-engaging means on said disc-shaped member and sleeve to afford frictional contact and separation of said disc-shaped member with said collar, a stud in operative engagement with said disc-shaped member, and spring means for normally urging said disc shaped member inoperative engagement with said collar to preclude relative dis-- placement between said stud and disc-shaped member. l i

6. In a device of the character described, the combination with a pusher rod adapted for reciprocationinalignment with an engine valve, there being an elongated bore in said pusher rod, a tubular collar rotatively mounted in said pusher rod bore, a disc-shaped member adapted for surfacecontact withjsaid collar and pusher rod, inter engaging means on said disc-shaped member and sleeve to afford frictional contact and separation of said disc-shaped member with said collar,'a stud in operative engagement with said disc-"shaped member, inter-engaging means on said stud and collar to'preclude relative rotation and enable reciprocable movement therebetween,

and spring means for normally urging said discshaped nirhber in operative engagement with said collar and pusher rod to preclude relative displacement between said stud and disc-shaped member.

7. In a device of the character described, the combination with a pusher rod adapted for reciprocation in alignment with an engine valve, there being an elongated bore in said pusher rod, a tubular collar rotatively mounted in said pusher rod bore, a disc-shaped member adapted for surface contact with said collar, inter-engaging means on said disc-shaped member and sleeve to preclude relative rotation and enable longitudinal movement therebetween to afford frictional contact and separation of said disc-shaped member with said collar, a stud in operative engagement with said disc-shaped member, inter-engaging means on said stud and collar to preclude relative rotation and enable reciprocable movement therebetween, and spring means for normally urging said disc-shaped member in operative engagement with said collar to preclude relative displacement between said stud and discshaped member.

8. In a device of the character described, the combination with a pusher rod adapted for reciprocation in alignment with an engine valve, there being an elongated bore in said pusher rod, a tubular collar rotatively mounted in said pusher rod bore, a disc-shaped member adapted for surface contact with said collar, inter-engaging means on said disc-shaped member and sleeve to preclude relative rotation and enable longitudinal movement therebetween to afford frictional contact and. separation of said disc-shaped member with said collar, a stud in operative engagement with said disc-shaped member, interengaging means on said stud and collar to preclude relative rotation and enable reciprocable movement therebetween, spring means for normally urging said disc-shaped member in operative engagement with said collar to preclude relative displacement between said stud and discshaped member, and an axially apertured cap mounted on said stud for cooperation with said disc-shaped member to confine said spring member therebetween.

9. In a device of the character described, the combination with a pusher rod adapted for reciprocation in alignment with an engine valve, there being an elongated bore in said pusher rod, a. tubular collar rotatively mounted in said pusher rod bore, a disc-shaped member adapted for surface contact with said collar, inter-engaging means on said disc-shaped member and sleeve to afford frictional contact and separation of said disc-shaped member with said collar, a stud 7 having a high-pitched exterior thread thereon in operative engagement with said disc-shaped member, and spring means for normally urging said disc-shaped member in operative engagement with said collar to preclude relative displacement between said stud and disc-shaped member.

10. In a device of the character described, the combination with a pusher rod adapted for reciprocation between an engine valve stem and an actuating cam, of a collar rotatively mounted in said pusher rod, an elongated member axially movable in said collar to engage the extremity of the engine valve stem, a relatively rotatable member in frictional contacting relation with said collar and pusher rod, said frictional member being operatively responsive to said elongated member, and spring means for normally maintaining said relatively rotatable members in frictional contact to normally preclude axial displacement of said elongated member relative to said pusher rod.

11. In a device of the character described, the combination with a pusher rod adapted for reciprocation between an engine valve stem and an actuating cam, of a collar rotatively mounted in said pusher rod, an exterior threaded elongated member axially movable in said collar to engage the extremity of the engine valve stem, a relatively rotatable member in frictional contacting relation with said collar and pusher rod, said frictional member being operatively responsive to said elongated member, and spring means for normally maintaining said relatively rotatable members in frictional contact to normally preclude axial displacement of said elongated member relative to said pusher rod.

oscAR F. FREDRICKSON. 

